Kverkarhellir cave is a deep artificial cave that was dug out of soft rock.

New research indicates that construction on it began in ca. AD 800, nearly

70 years before the Vikings are believed to have settled Iceland.

Photo by Tom McGovern

Seljalandshellar cave is a three chambered artificial cave located nearKverkarhellir. On its walls 23 carvings of the cross have been found.A typological analysis reveals that they are similar to crosses drawnin western Scotland in AD 800 and earlier. Photo by Kristján Ahronson

One of the crosses found in Seljalandshellar cave. Analysis indicatesthat it is similar to those carved in western Scotlandin AD 800 and earlier. Photo by Kristján Ahronson.

﻿﻿It is now thirty years since clerics, who live on the island [Thule] from the first of February to the first of August, told me that not only at the summer solstice, but in the days round about it, the sun setting in the evening hides itself as though behind a small hill in such a way that there was no darkness in that very small space of time... – Dicuil, an Irish monk, writing in AD 825, translation by J.J. Tierney.

New archaeological discoveries show that Iceland was inhabited around AD 800 – nearly 70 years before the traditional dating of its Viking settlement.

One possibility is that these early inhabitants may have been related to Irish monastic communities found throughout the Scottish islands at that time, and described in Viking-Age and medieval texts.

“Questions surrounding Iceland’s first settlement in the early medieval period have been of longstanding interest for scholars,” said Professor Kristján Ahronson of Prifysgol Bangor University in Wales and Visiting Professor at the University of Toronto. He led the team that made the discoveries.

As an example of the longstanding interest in this topic, Ahronson pointed to the University of Toronto’s Sir Daniel Wilson, who argued in 1851 that “when Norseman first visited Iceland in the latter half of the 9th century, it was uninhabited, but they discovered traces of the former presence of Irish monks.”

Kverkarhellir cave

One discovery was made at Kverkarhellir cave, on the land of Seljaland farm in southern Iceland. The cave is 7.5 metres long, and dug out of soft rock. Nearly 200 of these artificial caves have been found on the island. “Tool marks on the cave walls vividly illustrate the artificial nature of these sites,” said Professor Ahronson.

What makes Kverkarhellir special is the preservation of layers of sediments outside the cave mouth, specifically those from nearby volcanoes. Iceland has experienced many volcanic eruptions in its time. When an eruption takes place, a layer of ashy material known as “tephra” is deposited on the surface.

Ahronson said that these tephra layers are a “powerful dating tool,” which can be used to study past land surfaces and any artefacts found in these sediments. With this in mind the team went to work, digging just outside the entrance of the cave. As expected they encountered these tephra layers, including one from an eruption that happened around AD 871.

But when they dug deeper, unearthing older layers of sediments, they found something else. Ahronson said that they discovered “waste material from an episode of construction” – evidence of early activity at this cave. This discovery identifies Kverkarhellir cave as “older than any other site currently known in Iceland.”

To determine how early this presence was, the team measured the amount of wind-blown sediment that lies between the tephra and the waste material.

“Using the generally accepted but rough estimates for sediment accumulation in the area, (we have) a date of around AD 800,” said Ahronson, “though very local factors (affecting sediment accumulation) pose a challenge to precise dating.”

Animal tracks discovered dating to AD 871

To learn more about southern Iceland’s past environment, Ahronson’s team analyzed the form of tephra layers, looking at how they fell onto the ground.

If there are trees or a thick understory of vegetation, the ashy material will not land in some places, leading to gaps or features in the tephra layer. Also if an animal walks over tephra their footprints may be preserved.

The team plotted these irregularities out in 3D. This is a new technique involving excavation and mapping, initially tested over a small area - three by two meters in size.

Nevertheless the team achieved clear results – including the fascinating discovery of possible animal tracks.

“Unexpected linear depression features were found in the tephra layer,” said Ahronson. “The size, shape and distribution, hold out the possibility that these were created by medium-sized herbivores, such as sheep or small- and medium- sized cows.”

The tracks date back to around AD 871, many decades after the new evidence for people at Kverkarhellir cave, but just about when the large-scale settlement of Iceland by Vikings is generally thought to have begun.

The only larger mammals native to the island before humans arrived were arctic fox – which these tracks do not belong to.

A grassland environment in AD 871

There’s more.

The team discovered that these animals would have been walking over open grassland. When they analyzed the form of the tephra layer they found that, aside from the footprints, it was continuous and well-defined without “holes” or irregular gaps. In other words, there was little vegetation obstructing the volcanic material as it fell upon the ground.

“Interpretation of this data suggests an open grassland environment without tree cover,” Ahronson said.

He said that there could be two reasons for this – some sort of natural process that kept this area free of trees. Or, it could be that humans were responsible for deforestation in the area. “Woodland clearance would probably have occurred several decades before AD 870 in order to produce such an open and well defined tephra layer.”

Curiously it looks as if the area was reforested sometime later. When the team analyzed tephra from an eruption around AD 920, they found that it contained “a number of medium-sized irregularly shaped gaps,” Ahronson said. “These were interpreted to be the result of a lush understory of vegetation.” A sign, perhaps, that Vikings and their animals had abandoned this area, or that its woodland was being managed.

Crosses in caves

A second cave site at Seljaland, close to Kverkarhellir, contains possible evidence of early occupation.

It’s known as the Seljalandshellar cave group and contains 19 large and 4 mid-sized carvings on its walls - representing the Christian symbol of the cross. The team has been recording this art, and creating detailed illustrations of it.

Ahronson emphasized that it is difficult to firmly date these carvings; however, he notes that their style is similar to early medieval crosses seen in western Scotland.

“Typological analysis of many key characteristics of this material – leaves us to note fundamental parallels, specifically with the early medieval sculpture from the west highlands and islands,” he said. “In western Scotland, we would generally see most of this comparable material as predating the Viking Age,” in other words AD 800 or earlier.

He added that “none of the sculpture from Seljaland, intriguingly, has any parallels we can identify with Scandinavian traditions at that time.”

A layer of Tephra from ca. AD 920. The light spot indicates an area wherethe trunk of a tree may have been. Photo by Kristján Ahronson